Method for forming a closure for paper bags



Jan. 1, 1946. H. E. CLAYTON FOR FORMING A CLOSURE FOR PAPER BAGS 2Sheets-Sheetl Filed' March 1 .5, 1941 INVENTOR jfirggEC'ZayZom W 0Q:-

ATTORNEY Jan. 1, 1946. H. E. CLAYTON 2,391,946.

METHOD FOR FORMING A CLOSURE FOR PAPER BAGS 7 Filed March 15, 1941 2 Sheets-Sheet 2 INVENTOR E CZa fo z ATTORNEY Patented Jan. 1, 1946 METHOD Fort FORMING A oLosUau roa' PAPER BAGs Harry E.-Clayton, Holland, N. Y., assignor, by

mesne. assignments, to Bagpak, Inc., a corporav tion of Delaware Application March '15, 1941, Serial ud asaasa 1 Claim. (c1. 112 -262) This invention relates to new and useful improvements in stitch formations and the method of forming stitches and, particularly, seeks to pro-' vide a novel seam for use in connection with the closure formation of filledbags or the like.

Heretofore when iilled paper bags or the like have been closed and sealed by the formation of a line of stitches across the forms of seams have been employed as well as various types of stitch formation. 7 It has been known to employ a single thread, chain stitchto secure the bag closure in its completely folded position iormed closure, various.

' catenated loops of'the wherein the collapsed bag mouth is folded back upon itself or to employ a double thread chain stitch for the same purpose. In the instances where the single thread chain stitch was employed, it has been observed that-neither the thread entering the work on the needle side nor the interconnected loops on the work support side were so disposed or so proportioned that the apertures formed by the passage of the needle through the work were substantially sealed. Thus, the stitch closing of these forms of bag closures present difllculties in maintaining the bags in a siftproof condition. In those types of stitched bag closures which employed the double thread chain stitch, it has been observed that substantially the samev condition held true but to asomewhat less degree since the second series of interconnected loops formed by the looper threadof the double thread chain stitch provided reasonably effective means for sealing those sides of the needle apertures which were presented towards the work support.

The above mentioned difficulties in connection with the formation of stitched bag closures through the employment of either single thread or double thread chain stitches have been overcome through the use of this invention by which both ends of each individual needle aperture formed in the work are substantially sealed by certain portions of the loops comprising the stitches.

structed-in accordance with this Another object of this invention is to provide a method for forming a seam of the character stated in which the loops of the auxiliary thread will substantially plug the needle apertures on the needle side of the work and in which the conneedle and looper threads will substantially plug the apertures of the work on the work support side. 1

With these and other objects in view, the nature of which will become more'apparent; the inven-.

tion will be more fully understood by reference to the drawings, the accompanying detailed descziption, and the appended claim.

In the drawings: Fig. 1 is a fragmentary elevation of the closure portion of a bag including a stitch formation coninvention and taken from the needle side or the work;

Fig. 2 is a horizontalsection taken on lin 2-2 of Fig. 1;

Fig. 3 is a horizontal section taken on line 3-3 Fig. 4 is a vertical transverse sectiontaken on line l---l of Fig. 2;

Figs. 5 to 8 inclusive are somewhat convention-v alized figures illustrating a complete cycle in the formation of a stitch constructed in accordance with this invention;

It is, therefore, an object of this invention to i provide a novel method for forming a closure for paper bags which comprises a seam of the double thread chain stitch type which employs an auxiliary or binding thread serially formed into a plurality of spaced loops located upon the needle side 0! the work and encompassing the base portion of each needle thread loop.

Another object of this novel method for forming a seam adapted for particular use in connection with the securing of bag closures and which will maintain such closures in a substantially siftproof condition.

invention is to provide a Fig. 9 is a fragmentary detail vertical elevation taken along line 99 of Fig.5; A

Fig. 10 is a fragmentary detail verticalelevation taken along line i0-l 0 of Fig. 6;

Fig. 11 isa fragmentary detail vertical elevation taken alongline ll-H of Fig. 7;

Fig. 12 is a iragmc tary detail vertical elevation taken along line li -43.91 Fig. 8; and

Fig. 13 is a motion ili agram of theauxiliary looper elements. 7

Referring to the drawings in detail, the invention as illustrated is embodied in the closure seam of a filled paper bag or the like. As the invention resides particularly inthe stitch formation included in the scam, the bag material 5 will be hereinafter referred to as the work." The two or more layers of material which comprise the work 5 aresecured together by a novel. modified two-thread chain stitch including a needle thread 6, a looper thread I, and an auxiliary or binder thread 8. The needle and looper threads together define a plurality of serially side of the-seam; The needlesideof the seam presents. the normal' appearance of a. series of and, in addition.- thread 8 which. is formed into a plurality of spaced connected loops which encompass the base portions of the respective needle thread loops on the needle side of the work. Thus, this modified two-thread chain stitch presents a stitch formation which is particularly adapted for use in :conjunction with the closures of filled paper bags or the like, since the concatenated loops of the needle and looper threads on one side of the seamyvill ef fectively seal the needle apertures and the loops' of the auxiliary or binder thread will effectively seal the needle apertures on the other side of the seam to thereby provide a bag closure seam which is substantially siftproofin nature.

In Figs. 5 through 8 of the drawings, there is illustrated the manner by which this stitch may be formed. In Fig. 5 the needle 9 together with an auxiliary loop forming fork II and an auxiliary looper I3 are shown in their proper relative positions duringthe first stage of a stitch formation, the needle being at the beginning of its retractive stroke. In Fig. 6 the needle!) has been retracted from engagement with thework and the main looper has been projected through the loop of the needle threadi. At this stage of the cycle of stitch formation, the auxprovided through the use of prior known stitch paths of travel of the loop forming fork H and the auxiliary looper l3.

It is readily apparent that the novel, modified double thread chain stitch, formed in accordance with this invention, provides several advantages, particularly in connection with the closing of filled paper bags, which have not heretofore been formations. It should be noted that the auxiliary or binder thread 8 rests flatly against the bag surface and therefore substantially and tightly encompasses the ,base portions of the needle 7 .thread loops, and thus substantially seal the needie apertures: on the needle side of the work, and the concatenations of the needle and looper threads effectively seal the needle apertures on the work support side of the work and a substantially siftproof seam is thereby produced. Since the auxiliary thread 8 is formed into a series of spaced loops joined by connecting thread portions, the whole of which lies flat against the adiacent'surface of the work, any pull or strain tending to compact the needle thread and looper iliary looper l3 has moved upwardly and-forwardlyto the left to engage the auxiliary or binder thread around the loop forming fork ll, one arm of which is provided with a bifurcated end l2 adapted to receive the thread}. shown in Fig. 7, the previously formed stitch has been partly tightened by feed of the work throughthe' machine and the auxiliary looper l3 has completed that portion of its cycle of movement necessaryto effect the formation of a loop in the thread 8 around the auxiliary looper fork l l. The needle 9 at this stage of the cycle of stitch formation is approaching the work preparatory to the formation of another stitch. In

Fig. 8 the-feed step of the work through the machine has been completed and the:needle 9 has been propelled through the loop formed in the auxiliary or binder thread 8 and isready to pierce the work for the formation of another stitch. Figs. 9, 10, 11 and 12 of the drawings are elevational views which respectively correspond to Figs. 5, 6, 7 and 8 and more clearly Show the exact manner bywhich a loop is formed in the auxiliary or binder thread 8. It should be noted that the loop forming fork II is oscillated laterally in order to effect the disengagement thereof" from the auxiliarythread 8 subsequent to the engagement of the needle 9' within the loop formed in the thread 8; and to position the loop forming fork in its proper loca tion to be again engaged by the auxiliary thread thread portions of the stitches together will be resisted by the tensile" strength of the aux liary thread 8. Thus, the formed stitches cannot collapse or be drawn together without first breaking the auxiliary'thread. Furthermore, the provision of the auxiliary thread'in the manner illustrated tendsto prevent rupturing; of the stitch formation as a result of tearing of the bag material between adjacent needle holes under imposed strains. In connection with the imposition of strains upon a seam constructed in accordance with this invention, as the strain on the seam" becomes greater within the limits of strength of the stitch formation, ther will be a correspondingly greater effective action of the auxiliary thread loops in plugging the needle aperturessincje there will be a tendency to draw the auxiliary loops on the needle side, as well as the concatenations on the work support side, through the apertures toward each other. Preferably, the

8 preparatoryto the formation -of the next succeeding stitch. It should be further noted that the auxiliary looper element 13 travels in a generally elliptical path, the plane of which is dis-- of the needle 9 in order that the loops which are formed in the auxiliary thread 8 may be directly positioned within the path of travel of the needle Fig. 13 isa'motion diagram illustrating the auxiliary or binder thread 8, during the stitch forming operations, is drawn under the same degree of tension as the looper and needle threads in order that all slack may be full taken up at the end of the formation of each stitch.

It is of course to be understood that certain details of arrangement and proportions of parts maybe variously modified without-exceeding the scope of the appended claim.

I claim:

In a method of forming a closure for paper ba pri a seam of the double-thread chain-stitch type having a supplementary binder thread associated therewith, the steps of forming a loop in a binder thread, passing athreaded needle through-said loop and then through the bagand then through a previousl formed looper thread loop, retracting the' needle to define a v posed angularly with respect to the path of travel 7 needle thread loop, inserting a threaded looper into-said-needle thread loop duringjthe retractive movement of said needle, further retracting theneedle to disengage it from said bag and from said binder thread loop, feeding the bag to tighten the previously formed stitch, and repeating the steps in the order named.

- HARRY E. CLAYTON. 

